The need to decrease energy usage and subsequent emissions from the building sector has been at the forefront of U.S. green movement. Not only has energy reduction been viewed as a step for improving the environment, it has financial benefits for companies and homeowners.
To address this, researchers at the Massachusetts Institute of Technology’s (MIT) Concrete Sustainability Hub conducted a life-cycle assessment (LCA) study to evaluate and improve the environmental impact and study how the “dual use” aspect of concrete – its ability to offer a durable structure while providing thermal mass benefits for energy loads – affects the environmental footprint of the structure.
"Methods, Impacts, and Opportunities in the Concrete Building Life Cycle" provides a comprehensive analysis that advances three key areas relevant to the buildings LCA field: methodology, benchmarking, and impact-reduction opportunities. The study is a major development for construction-related life-cycle assessment because it thoroughly examines all phases of the complete life cycle of a building – from acquisition of materials to construction, the use of the building, and finally demolition and end of life.
“Most environmental assessments do not move beyond the construction phase and only provide a partial picture of the full impact a particular material can have on a building. This is short-sighted,” David Shepherd, director of sustainable development for the Portland Cement Association (PCA) said. “The heating, cooling, and general operations of buildings and homes in the United States accounts for approximately 70 percent of national energy consumption each year and an accurate LCA needs to include the operational phase.”
Concrete, essential for the construction of buildings and homes, has largely been chosen as a building material for its structural properties rather than its energy-saving properties. Although sustainable builders have known the thermal mass attributes of concrete significantly reduce heating and cooling needs, the energy consumption required to produce its key ingredient, cement, has raised questions about its environmental viability.
In its environmental assessment, MIT researchers found concrete homes produce lower greenhouse gas emissions than current best practice code – compliant wood-frame residences throughout a 60-year service life.
Concrete homes did have a higher embodied global warming potential (GWP) associated with the pre-use phase of LCA when raw materials are harvested and turned into construction materials, transported to the site, and assembled into the finished home. However, this phase accounts for only about 2 to 12%of the overall global warming potential for the life of the home. For the 60-year period of the study, houses constructed with insulated concrete forms have 5 to 8 percent lower GWP than current code compliant light frame wood houses, based on greater thermal mass and higher R-values. Researchers found similar results when evaluating multifamily residences.
Commercial office buildings built with a concrete structural frame produce slightly less greenhouse gas emissions over a 60-year service life than commercial structures built with steel frames, based on the results of the comprehensive MIT assessment.
MIT researchers then evaluated strategies to lower a concrete building’s carbon footprint and overall environmental impact. A major advancement was the incorporation of a cost-impact analysis to determine whether or not a given environmental reduction strategy made economic sense. Among the strategies evaluated, the two that reduced embodied emissions – increased fly ash and reducing the thickness of concrete walls from a 6-inch to a 4-inch concrete core – were found to be both economical and effective ways to reduce emissions. BD+C
Related Stories
Architects | May 20, 2015
Architecture billings remain stuck in winter slowdown
Regional business conditions continue to thrive in the South and West
University Buildings | May 19, 2015
Special Report: How your firm can help struggling colleges and universities meet their building project goals
Building Teams that want to succeed in the higher education market have to help their clients find new funding sources, control costs, and provide the maximum value for every dollar.
University Buildings | May 19, 2015
Renovate or build new: How to resolve the eternal question
With capital budgets strained, renovation may be an increasingly attractive money-saving option for many college and universities.
University Buildings | May 19, 2015
KU Jayhawks take a gander at a P3 development
The P3 concept is getting a tryout at the University of Kansas, where state funding for construction has fallen from 20% of project costs to about 11% over the last 10 years.
Multifamily Housing | May 19, 2015
Zaha Hadid unveils 'interlocking lattice' design for luxury apartments in Monterrey, Mexico
Hadid's scheme was inspired by the Mexican tradition of interlocking lattice geometries.
Retail Centers | May 18, 2015
ULI forecast sees clear skies for real estate over next three years
With asset availability declining in several sectors, rents and transactions should rise.
Architects | May 17, 2015
NCARB wants the title ‘architect’ confined to those who are licensed
The Council is urging state licensing boards to come up with a substitute for the pre-licensure title ‘Intern.’
Museums | May 13, 2015
The museum of tomorrow: 8 things to know about cultural institutions in today’s society
Entertainment-based experiences, personal journeys, and community engagement are among the key themes that cultural institutions must embrace to stay relevant, write Gensler's Diana Lee and Richard Jacob.
Industrial Facilities | May 11, 2015
SOM-designed Manufacturing and Design Innovation Institute opens in Chicago
The new space will be a place for academia, industries, and civic bodies to collaborate.
Sponsored | Roofing | May 11, 2015
How architects can tap into the expertise of their metal roof manufacturer, part 2
Here are three things metal roof manufacturers can do to help the architect